Common (Translated Scientific) Name: Alderleaf Mountain-mahogany / New Mexico Feathergrass Shrubland

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This is a major community throughout the San Andres and Oscura mountains of New Mexico. This type may occur elsewhere in the Southwest, the Rocky Mountains, and possibly northern Mexico. This association occurs on moderate to steep slopes. It is commonly found on nose or sideslopes of escarpment faces, or along dip slopes. It can also occur on alluvial deposits of mountain valleys or upper portions of basin alluvial fans. It occurs predominantly on northerly aspects at elevations of 1520 to 2130 m (5000-7000 feet). Substrates are typically Paleozoic limestone. However, stands can occasionally occur on sandstone. Escarpment stands are characterized by loose rock and gravel with occasional scattered boulders. Dip slope stands (low to upper slopes) are characterized by loose rock and gravel overlaying bedrock; bedrock exposure is typically high. Soils are derived from limestone and are generally distributed in patchy accumulations or between fractures in the bedrock. Soils are typically shallow with horizons of silt loam to clay loam in a rocky matrix (loamy and clayey skeletal Mollisols and Aridisols). Surface textures generally range between sandy loam and silty clay loams. This community is characterized by a shrub layer clearly dominated by Cercocarpus montanus, with a grassy understory dominated by Hesperostipa neomexicana. The shrub canopy can be very open with Cercocarpus montanus widely spaced and tall and with low-lying shrubs scattered in between. Yucca baccata, Viguiera stenoloba, Rhus trilobata, Opuntia phaeacantha, Nolina microcarpa, Krascheninnikovia lanata, and Dalea formosa are common associates of this diverse shrubland (36 shrubs). Pinus edulis and Juniperus monosperma (juvenile, mature, or standing dead) are common in higher elevation stands. The grass layer is well-represented to luxuriant in cover. Bouteloua curtipendula and Aristida purpurea may occasionally codominate with Hesperostipa neomexicana. Other common grasses are Eragrostis intermedia, Muhlenbergia setifolia (near ridgetops), Bouteloua eriopoda, and Bouteloua gracilis. Forb diversity is moderate (26 species). Viguiera dentata grows near shrub canopies. Melampodium leucanthum, Chamaesyce fendleri, Tetraneuris scaposa, and Lesquerella fendleri are also common, but generally grow in between shrubs.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: On White Sands Missile Range, stands of this association (CEGL002911) occur in patches across the San Andres Mountain escarpment and become more continuous on dipslopes. In the Oscura Mountains, stands occur in bands along upper piedmonts (western slope) and become patchy in the foothills. This association can be found embedded in a matrix of pinyon and juniper associations, and may be successional to open woodlands such as ~Juniperus monosperma / Hesperostipa neomexicana Open Woodland (CEGL000722)$$ or ~Juniperus monosperma / Bouteloua gracilis Open Woodland (CEGL000710)$$ and, possibly Pinyon Pine/New Mexico Needlegrass PA (Muldavin et al. 2000b). It can exist near pinyon-pine-lined drainages or grade to other Cercocarpus montanus associations, such as ~Cercocarpus montanus / Bouteloua curtipendula Shrubland (CEGL001086)$$ or Mountain Mahogany/Plains Lovegrass PA (Muldavin et al. 2000b). Lower elevations or adjacent warmer slopes generally grade into grasslands, including ~Bouteloua eriopoda - Bouteloua gracilis Grassland (CEGL001748)$$, ~Bouteloua hirsuta - Bouteloua curtipendula Grassland (CEGL001764)$$, Black Grama/Blue Grama/Banana Yucca PA (Muldavin et al. 2000b), or Quercus turbinella associations, such as ~Quercus turbinella / Bouteloua eriopoda Shrubland (CEGL000978)$$ or Shrub Live Oak/Sideoats Grama or Shrub Live Oak/Black Grama PA (Muldavin et al. 2000b). In the San Andres Mountains, stands across foothill escarpments are generally bound by rock outcrops and thus occur in linear bands. Higher elevations or adjacent, cooler slopes support pinyon or juniper woodlands. Cercocarpus montanus stands in New Mexico occurring at lower elevations tend to have open canopies (this may be related to fire intensity and frequency) with substantial herbaceous understories.

Similar NVC Types: No Data Available

note: No Data Available